1. Field of the Invention
The present invention relates to a sheet bundle binding processing apparatus which performs a binding process on sheets fed from an image forming apparatus or the like after stacking the sheets into a bundle shape, and relates to improvement of a sheet bundle discharging mechanism with a non-staple binding unit which bonds mutually overlapped sheets with pressure deformation.
2. Description of Related Arts
In general, as a post-processing apparatus, there has been widely known an apparatus which performs a binding process with a binding processing unit after stacking, on a processing tray, sheets fed from an image forming apparatus and stores the sheets on a stack tray at the downstream side. In a structure thereof, a sheet introducing path is connected to a sheet discharging port of an image forming apparatus, image-formed sheets are collated and stacked on the processing tray arranged at the sheet discharging port, a binding process is performed on the sheets with the binding processing unit arranged at the processing tray, and then, the sheets are stored in a stack tray at the downstream side.
A binding processing unit which performs a binding process using a staple has been widely used for such a post-processing apparatus. Here, to solve problems in difficulty of sheet separation, disposal of bound sheets (shredding and the like), and the like, binding processing units without using a staple have been variously evaluated.
For example, Japanese Patent Application Laid-open No. 2011-190021 discloses a structure for an operator to select a staple binding process or a non-staple binding process to be performed on a sheet bundle stacked on a processing tray from a sheet discharging port of an image forming apparatus. For performing the non-staple binding process, there are disclosed a unit to mutually bond sheets as pressure-contacting a pair of corrugation-shaped pressurizing faces and a post-processing mechanism using the same.
Here, it is disclosed, as in FIG. 11 of the above application, a bonding method to bond a sheet bundle as pressure-nipping the sheet bundle with a convex pressurizing face and a concave pressurizing face which are to be mutually engaged. According to such a bonding method, there are features that a bonding mechanism is relatively simple, a sheet bundle is easily separated, and disposal of bound sheets (shredding and the like) are easy. On the contrary, it is difficult to obtain reliable bonding and the number of sheets to be bound is limited.